code: def __call__(self, sparse_data):
      return self.process(sparse_data)
  
file_path: ReAgent/reagent/preprocessing/sparse_to_dense.py
imports: from collections import defaultdict
  from typing import Dict, List, Tuple
  import torch
  from reagent.preprocessing import normalization
label_desc: Use image node_id 2 for calling the SparseToDenseProcessor obj's underlying member method code with example usage: obj.__call__(sparse_data) and returns: self